Exhaust emissions from internal combustion engines present serious environmental concerns. Motor vehicle exhaust emissions, in particular, present a serious, unchecked problem in many large cities. The emissions not only contribute to the smog and pollution problems of many large metropolitan areas, resulting in the silent, continual destruction of the ozone layer, but may also cause long term health effects due to their potential toxicity. In an attempt to regulate the levels of potentially harmful pollutants in the environment, the Environmental Protection Agency promulgated new emissions standards, setting forth acceptable levels of carbon monoxide, nitrogen oxides, particulate matter and hydrocarbons in the exhaust emissions of various classes of motor vehicles. The new standards will be implemented in phases, beginning with the 1994 model year.
The hydrocarbon content of vehicle emissions is indicative of the fuel burning efficiency of the engine. The higher the percentage of hydrocarbon (HC) emissions, the lower the level of hydrocarbons efficiently burned. The carbon dioxide (CO.sub.2) content of the emissions reflects the combustion efficiency and catalytic action of the engine and fuel components. The higher the carbon dioxide content, the more efficient the combustive process. The carbon monoxide (CO) content of the emissions is indicative of the level of combustion in the engine chamber. A high percentage of carbon monoxide in motor vehicle emissions, often caused by a lean air to fuel ratio, is indicative of incomplete combustion in the engine chamber. A high molecular oxygen (O.sub.2) content in the emissions could mean a lean fuel to air ratio or fouled plugs. Ideally, motor vehicle exhaust emissions contain low percentages of hydrocarbons, carbon monoxide and molecular oxygen, and a high percentage of carbon dioxide.
The use of a fuel additive in an internal combustion engine to improve combustion is well-known in the art. For example, it is known in the art that a fuel additive containing various metals may reduce soot build-up on an internal combustion engine and thereby improve combustion. Kukin U.S. Pat. No. 3,348,932, for example, discloses a fuel additive containing combinations of various metals designed to effectively reduce soot build-up.
It is also known in the art that organic aromatic and aliphatic components used in concert may increase the power of the fuel. For example, one early fuel additive described in Ferrer U.S. Pat. No. 1,496,260, used a combination of acetone (C.sub.3 H.sub.6 O), camphor (C.sub.10 H.sub.16 O), naphthalene (C.sub.10 H.sub.8), methyl alcohol (CH.sub.3 OH), diethyl ether (C.sub.2 H.sub.5).sub.2 O and amyl alcohol (C.sub.5 H.sub.11 OH) both to increase the power of the fuel and to help keep the engine cylinders and pistons free from carbon.
It is also known in the art that certain combinations of organic aromatic and aliphatic components added to fuel may improve engine performance and decrease certain motor vehicle emissions. For example, Savage U.S. Pat. No. 2,088,000 describes a motor fuel additive composed of varying quantities and combinations of alcohol, naphthalene and acetone. Though use of a small amount of the Savage additive in motor fuel results in improved engine performance and a decreased percentage of carbon monoxide in exhaust emissions, Savage does not disclose a decrease in the percentage of either hydrocarbons or molecular oxygen emitted, nor does it disclose an increase in the percentage of carbon dioxide emitted.
Along the same lines, Villacampa U.S. Pat. No. 3,925,031 is directed toward a fuel additive consisting of various organic components including naphthalene, camphor, toluene and benzyl alcohol, as well a gasoline fraction. A small weight percentage of a C.sub.1 -C.sub.8 alkyl alcohol may also be included in the Villicampa composition. Use of the Villacampa additive results in increased horsepower of the internal combustion engine utilizing the fuel, a reduction in the fuel oil consumption rate, and reductions in hydrocarbon output, carbon monoxide output and nitrous oxide production. Though the Villacampa patent discloses a potential 46% decrease in hydrocarbon emissions and a potential 55% decrease in carbon monoxide emissions through use of the Villacampa additive, neither an decrease in molecular oxygen output nor increase in carbon dioxide in the emissions is disclosed.
Dorn et al. U.S. Pat. No. 4,806,129 is directed toward an oxygenated fuel extender comprised of naphtha, anhydrous ethanol, water repellants of the class consisting of ethyl acetate and methyl isobutyl ketone, and various aromatic compounds such as benzene, toluene and xylene. The purpose of the Dorn et al. extender is to serve as a fuel substitute, resulting in a decreased amount of actual fuel usage and, hence, a lower fuel cost. Dorn et al. does not disclose decreased emissions as an object of the extender.
Chikul et al. U.S. Pat. No. 4,180,385 describes a fuel composition containing a high-boiling petroleum fuel and an additive that includes, as a principal ingredient, an ash-containing resin derived from the thermal processing of a solid fuel. Though Chikul, like the present invention, does contemplate the inclusion of metal oxides such as magnesium oxide and iron oxide in the composition, it does not disclose inclusion of any organic components such as those contemplated by the present invention. Furthermore, though Chikul states as an objective the reduced pollution of the environment resulting from the combustion of the fuel composition, no reduced emissions statistics are disclosed. Instead, the patent focuses on the production of the ash-containing resin and its anti-corrosive effects.